But from what I gather, the character himself doesn't have any actual time-travelling powers? From the summary of the TV version of DoFP I've read, he just hops into the time-portal. So if he doesn't have the time-travelling powers, and has no real importance for achieving time travel, why make him the traveller? I can see the point if the whole story is basically from his point of view, but I rather doubt that they'll make him the main character.

Anyhow, from what Singer says it sounds like the time travel in this movie will somehow be less straightforward than just jumping into a time portal.

I think he said somewhere about it being power based or at least hinting at that direction. So, that suggest we might get Gateway, Fitzroy or something else.